The present invention relates to pigments which can be used in a variety of applications, and more particularly relates to the modification of pigments to improve various properties.
Pigments have been used in a variety of applications, such as in inks, coatings, toners, plastics, rubber, films, and the like. Common goals in each of these applications are to provide a pigment which is capable of being substantially and uniformly dispersed, and capable of remaining dispersed in the composition so that color and other properties exhibited by the pigment are uniform throughout the composition or material which incorporates the pigment. The improvement in the dispersibility and dispersion stability of pigments has been attempted previously and has included coating or adsorbing various surfactants onto the pigment. However, merely adsorbing or coating pigments had potentially several disadvantages. First, adsorbed surfactants are dependent on the physical properties of the surrounding materials, such as the solvent with the ink. In such a situation, an equilibrium may exist between the surface of the pigment and the solvent for surfactant affinity. Solubility issues involving the surfactant and the solvent may also come into effect. Other considerations which can effect adsorbed surfactants are the concentration of the pigment, the type of surfactants used, and the temperature and pH of the composition or material containing the pigment. Any one or more of these physical properties can cause the removal of the surfactant from the surface of the pigment and create additional surfactant in the bulk liquid or medium which may negatively effect the dispersion stability and other properties of the bulk liquid such as foaming, surface tension, viscosity, film strength, film elasticity, and the like. In addition, the excess surfactant which may be found in conventional pigments may also be detrimental to plastic or film-forming properties, such as color, strength, elongation, elasticity, and the like. Accordingly, there is a desire in the art to improve the dispersibility and dispersion stability of pigments with respect to overcoming one or more of the above-described disadvantages.
A feature of the present invention is to provide modified pigment products which are capable of improving the dispersibility and dispersion stability of the pigment in compositions and formulations.
Another feature of the present invention is to provide ink, coating, toner, polymer, paper, film, and rubber formulations which incorporate the modified pigment products of the present invention.
An additional feature of the present invention is to provide a method to improve the dispersibility and dispersion stability of pigments in various compositions and formulations.
Additional features and advantages of the present invention will be set forth in part in the description which follows, and in part will be apparent from the description, or may be learned by practice of the present invention. The objectives and other advantages of the present invention will be realized and obtained by means of the elements and combinations particularly pointed out in the written description and appended claims.
To achieve these and other advantages and in accordance with the purpose of the present invention, as embodied and broadly described herein, the present invention relates to a modified pigment product containing a pigment having attached at least one group comprising the formula:
xe2x80x94X-[NIon]pR
wherein X represents an aromatic group or an alkyl group, NIon represents at least one type of non-ionic group, R represents hydrogen, a substituted or unsubstituted aromatic group, Cr a substituted or unsubstituted alkyl group, and p represents an integer of from 1 to 500.
The present invention further relates to a modified pigment product containing a pigment having attached at least one group comprising the formula:
xe2x80x94X[A]pR
wherein X represents an aromatic group or an alkyl group; A represents an alkylene oxide group of from about 1 to about 12 carbons; p represents an integer of from 1 to 500, and R represents hydrogen, a substituted or unsubstituted alkyl group, or a substituted or unsubstituted aromatic group. A can be the same or different when p is greater than 1. X can be substituted or unsubstituted and can include substituted groups such as an ester group, an amide group, an ether group, a carbonyl group, an aryl group, an alkyl group, and the like. The substituted groups can be attached or linked to A.
The present invention in addition, relates to a modified pigment product containing a pigment having attached at least one group comprising the formula:
xe2x80x94Xxe2x80x94[(CH2)mxe2x80x94Oxe2x80x94]pR
wherein X represents an aromatic group or an alkyl group, m represents an integer of from 1 to 12, preferably 2 or 3, p represents an integer of from 1 to 500, and R represents hydrogen, a substituted or unsubstituted alkyl group, or a substituted or unsubstituted aromatic group.
Further, the present invention relates to a modified pigment product comprising a pigment having attached at least one polymeric group, wherein the polymeric group comprises the formula:
xe2x80x94X-[polymer]R
wherein X represents at least an aromatic group or an alkyl group, xe2x80x9cpolymerxe2x80x9d represents repeating monomer or multiple monomer groups or both, optionally having at least one Xxe2x80x2 group. The total monomer repeating units is from about 1 to about 500. R represents hydrogen, a bond, a substituted or unsubstituted alkyl group, or a substituted or unsubstituted aromatic group. When X represents an alkyl group, the xe2x80x9cpolymerxe2x80x9d preferably has no ionic or ionizable group. Xxe2x80x2 represents an aromatic group or alkyl group and each Xxe2x80x2 and X can be the same or different. X and/or Xxe2x80x2 can be substituted or unsubstituted and can include substituted groups such as an ester group, an amide group, an ether group, and the like. The substituted groups can be linked to xe2x80x9cpolymerxe2x80x9d. Also, when R represents a bond, the available bond can be attached to the pigment.
The present invention also relates to ink compositions containing at least one modified pigment product of the present invention and at least one ink vehicle.
The present invention also relates to coating compositions comprising at least one modified pigment product of the present invention and at least one coating vehicle.
The present invention also relates to toner compositions containing at least one modified pigment product of the present invention and resin particles.
Also, the present invention relates to a rubber products, polymer (e.g., plastics) products, and films containing conventional ingredients in combination with at least one modified pigment product of the present invention.
It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are intended to provide further explanation of the present invention, as claimed.
The present invention in general relates to various types of modified pigment products which are preferably capable of dispersing in a variety of materials including, but not limited to, liquids (aqueous and non-aqueous), polymers (e.g., thermoplastics and thermosets), elastomers (e.g., synthetic and/or natural rubbers), coatings (e.g., paints), inks (e.g., printing inks and inkjet inks), liquid and solid toners, films, and the like. The pigments are modified such that chemical groups (e.g., polymeric and organic) are attached onto the pigment which provides a more stable attachment of the groups onto the pigment compared to adsorbed groups, e.g., polymers, surfactants and the like.
In each of the following formulas, xe2x80x94X is attached directly to the pigment and xe2x80x94Xxe2x80x2 can be directly attached to the pigment.
One preferred modified pigment product is a pigment having attached at least one group comprising the formula:
xe2x80x94X-[NIon]pR
wherein X represents an aromatic group or an alkyl group, NIon represents at least one non-ionic group, R represents hydrogen, an aromatic group, or an alkyl group, and p is an integer of from 1 to 500.
The aromatic group with respect to the X substituent and/or the R substituent can be substituted or unsubstituted and can be, for instance, an aryl or heteroaryl group. The aromatic group can be substituted with any group, such as one or more alkyl groups or aryl groups. Preferably, the aromatic group is a phenyl, naphthyl, anthracenyl, phenanthrenyl, biphenyl, pyridinyl, benzothiadiazolyl, or benzothiazolyl. Examples of the alkyl group with respect to the X substituent and/or the R substituent include, but are not limited to, substituted or unsubstituted alkyl groups which may be branched or unbranched. The alkyl group can be substituted with one or more groups, such as aromatic groups. Preferred examples of the alkyl group for purposes of the X substituent include, but are not limited to, C1-C12, like methyl, ethyl, propyl, butyl, pentyl, or hexyl groups. In other words, X and/or R can represent a branched or unbranched, substituted or unsubstituted, saturated or unsaturated hydrocarbon. Examples of substituted groups include, but are not limited to, an ester group, an amide group, an ether group, a carboxyl group, an aryl group, an alkyl group, and the like.
Examples of the non-ionic group include, but are not limited to, groups having no apparent ionic charge, such as polymers of ethylene oxide, propylene oxide, other alkylene oxides, carboxylic acid esters, glycols, alcohols, esters, alkanolamine-fatty acid condensates, silicones, isocyanates, alkylpyrrolidenes, and alkylpolyglycosides. In non-aqueous media, the non-ionic group, in addition to the aforementioned groups, may have carboxylates, sulfonates, phosphates, amines, and other groups that typically demonstrate an ionic nature in water. The non-ionic group is preferably a C1-C12 alkyl group, or a C1-C12 alkylene oxide group. p can be 1-25,26-50, 51-75, 75-100, and/or 101-500, and p preferably is 5 to 50.
The X substituent and/or non-ionic group may be substituted with one or more functional groups. The functional group preferably contains a lypophilic group. Examples of functional groups include, but are not limited to, Rxe2x80x2, ORxe2x80x2, CORxe2x80x2, COORxe2x80x2, OCORxe2x80x2, carboxylates, halogens, CN, NRxe2x80x22, SO3H, sulfonates, xe2x80x94OSO3, NRxe2x80x2(CORxe2x80x2), CONRxe2x80x22, NO2, PO3H2, phosphonates, phosphates, Nxe2x95x90NRxe2x80x2, SORxe2x80x2, NSO2Rxe2x80x2, wherein Rxe2x80x2 which can be the same or different, is independently hydrogen, branched or unbranched C1-C20 substituted or unsubstituted, saturated or unsaturated hydrocarbons, e.g., alkyl, alkenyl, alkynyl, substituted or unsubstituted aryl, substituted or unsubstituted heteroaryl, substituted or unsubstituted alkyoaryl, or substituted or unsubstituted arylalkyl.
Amines also represent examples of functional groups as well as quaternary ammonium groups (xe2x80x94NR3+) and quaternary phosphonium groups (xe2x80x94PR3+), as well as quaternary sulfonium groups (xe2x80x94SR2+).
In an additional embodiment of the present invention, the modified pigment product can be a pigment having attached at least group comprising the formula:
xe2x80x94X [A]pR
wherein X represents an aromatic group or an alkyl group; A represents an alkylene oxide group of from about 1 to about 12 carbons; p represents an integer of from 1 to 500, and R represents hydrogen, a substituted or unsubstituted alkyl group, or a substituted or unsubstituted aromatic group. A can be the same of different when p is greater than 1. X can be substituted or unsubstituted and can include substituted groups such as an ester group, an amide group, an ether group, a carbonyl group, an aryl group, an alkyl group and the like. The substituted groups can be attached or linked to A.
Examples of preferred alkylene groups include, but are not limited to, xe2x80x94CH2xe2x80x94CH2xe2x80x94Oxe2x80x94; xe2x80x94CH(CH3)xe2x80x94CH2xe2x80x94Oxe2x80x94; xe2x80x94CH2CH2CH2xe2x80x94Oxe2x80x94; or combinations thereof.
In another embodiment of the present invention, the modified pigment product can be a pigment having attached at least one group comprising the formula:
xe2x80x94Xxe2x80x94[(xe2x80x94CH2)mxe2x80x94Oxe2x80x94)pxe2x80x94R]
wherein X is described above, and for instance can represent an aromatic group or an alkyl group as described earlier, m is an integer of from 1 to 12, preferably 2 or 3, p is an integer of from 1 to 500, and R is described above, and for instance can be hydrogen, a substituted or unsubstituted alkyl group, or a substituted or unsubstituted aromatic group. Examples of R substituents include, but are not limited to, hydrogen, methyl, ethyl, butyl, or propyl groups. p can be 1-25, 26-50, 51-75, 76-100, and 101-500, and is preferably 5 to 50. Particularly preferred groups of this formula are where X is a benzene group, m is 1 to 5, and more preferably 2 or 3, p is 5 to 50, more preferably 44-45, and R is hydrogen or a methyl group. Another preferred group is where m is 2, p is 7, R is a methyl group, and X is a benzene group.
In yet another embodiment of the present invention, the modified pigment product can be a pigment having attached at least one polymeric group, wherein the polymeric group comprises the formula:
xe2x80x94X-[polymer]R
wherein X is described above, and for instance can represent at least an aromatic group or at least an alkyl group as described earlier, xe2x80x9cpolymerxe2x80x9d comprises repeating monomer groups or multiple monomer groups or both, optionally having at least one xe2x80x94Xxe2x80x2 group. The xe2x80x98polymerxe2x80x99 can be substituted or unsubstituted with additional groups, and R is described above, and for instance can represent hydrogen, a bond, a substituted or unsubstituted alkyl group, or a substituted or unsubstituted aromatic group. When X represents an alkyl group, the xe2x80x9cpolymerxe2x80x9d preferably has no ionic or ionizable group. Xxe2x80x2 represents an aromatic group or alkyl group, and each Xxe2x80x2 and X can be the same or different. The total monomer repeating units that comprise the xe2x80x9cpolymerxe2x80x9d is not greater than about 500 monomer repeating units. X and/or Xxe2x80x2 can be substituted or unsubstituted and can include substituted groups such as an ester group, an amide group, an ether group, and the like. The substituted groups can be linked to the xe2x80x9cpolymer.xe2x80x9d Also, when R represents a bond, the available bond can be attached to the pigment. When X represents an alkyl group in this formula, the polymeric group preferably has no ionic or ionizable group. The polymeric group can be any polymeric group capable of being attached to a pigment.
For purposes of the present invention and this formula immediately above, one or more polymeric groups that comprise the xe2x80x9cpolymerxe2x80x9d can be present. The polymeric group can be a thermoplastic polymeric group or a thermosetting polymeric group. Further, the polymeric group can be a homopolymer, copolymer, terpolymer, and/or a polymer containing any number of different repeating units. Further, the polymeric group present in the present invention can be any type of polymeric group, such as a random polymer, alternating polymer, graft polymer, block polymer, star-like polymer, and/or comb-like polymer. The polymeric group used in the present invention can also be one or more polyblends. The polymeric group can be an interpenetrating polymer network (IPN); simultaneous interpenetrating polymer network (SIN); or interpenetrating elastomeric network (IEN).
Specific examples of polymeric groups include, but are not limited to, linear-high polymers such as polyethylene, poly(vinylchloride), polyisobutylene, polystyrene, polycaprolactam (nylon), polyisoprene, and the like. Other general classes of polymeric groups of the present invention are polyamides, polycarbonates, polyelectrolytes, polyesters, polyethers, (polyhydroxy)benzenes, polyimides, polymers containing sulfur (such as polysulfides, (polyphenylene) sulfide, and polysulfones), polyolefins, polymethylbenzenes, polystyrene and styrene copolymers (ABS included), acetal polymers, acrylic polymers, acrylonitrile polymers and copolymers, polyolefins containing halogen (such as polyvinyl chloride and polyvinylidene chloride), fluoropolymers, ionomeric polymers, polymers containing ketone group(s), liquid crystal polymers, polyamide-imides, polymers containing olefinic double bond(s) (such as polybutadiene, polydicyclopentadiene,), polyolefin copolymers, polyphenylene oxides, poly(vinyl alcohols), polyurethanes, thermoplastic elastomers, and the like.
Generally, the polymeric groups described in Volume 18 of the Encyclopedia of Chemical Technology, KIRK-OTHMER, (1982), page 328 to page 887, and Modem Plastics Encyclopedia ""98, pages B-3 to B-210, and xe2x80x9cPolymers: Structure and Properties,xe2x80x9d by C. A. Daniels, Technomic Publishing Co., Lancaster, Pa. (1989), all incorporated in their entirety herein by reference, can be used as the polymeric groups of the present invention.
The polymeric groups of the present invention can be prepared in a number of ways and such ways are known to those skilled in the art. The above referenced KIRK-OTHMER section, Modern Plastics Encyclopedia, and C. A. Daniels"" reference provide methods in which these polymeric groups can be prepared.
The polymeric group is preferably a polyolefin group, a polyurethane group, a polystyrenic group, a polyacrylate group, a polyamide group, a polyester group, or mixtures thereof. Examples of R groups can be the same as previously described above. p can be 1-25, 26-50, 5,1-75, 76-100, 101-500, and is preferably 1 to 100, and more preferably 5 to 50.
The pigment to be modified can be, but is not limited to, pigments traditionally used in ink compositions (including inkjet ink compositions), coating compositions (including paint formulations), liquid and solid toners, films, plastics, rubbers, and the like.
Examples include, but are not limited to, black pigments (e.g., carbon products like carbon black) and other colored pigments (e.g., polymeric and organic pigments).
The desired colored pigment may be chosen from a wide range of conventional colored pigments. The colored pigment can be blue, black, white, brown, cyan, green, violet, magenta, red, yellow, as well as mixtures thereof. Suitable classes of colored pigments include, for example, anthraquinones, phthalocyanine blues, phthalocyanine greens, diazos, monoazos, pyranthrones, perylenes, heterocyclic yellows, quinacridones, and (thio)indigoids. Representative examples of phthalocyanine blues include copper phthalocyanine blue and derivatives thereof (Pigment Blue 15). Representative examples of quinacridones include Pigment Orange 48, Pigment Orange 49, Pigment Red 122, Pigment Red 192, Pigment Red 202, Pigment Red 206, Pigment Red 207, Pigment Red 209, Pigment Violet 19 and Pigment Violet 42. Representative examples of anthraquinones include Pigment Red 43, Pigment Red 194 (Perinone Red), Pigment Red 216 (Brominated Pyanthrone Red) and Pigment Red 226 (Pyranthrone Red). Representative examples of perylenes include Pigment Red 123 (Vermillion), Pigment Red 149 (Scarlet), Pigment Red 179 (Maroon), Pigment Red 190 (Red), Pigment Violet, Pigment Red 189 (Yellow Shade Red) and Pigment Red 224. Representative examples of thioindigoids include Pigment Red 86, Pigment Red 87, Pigment Red 88, Pigment Red 181, Pigment Red 198, Pigment Violet 36, and Pigment Violet 38. Representative examples of heterocyclic yellows include Pigment Yellow 1, Pigment Yellow 3, Pigment Yellow 12, Pigment Yellow 13, Pigment Yellow 14, Pigment Yellow 17, Pigment Yellow 65, Pigment Yellow 73, Pigment Yellow 74, Pigment Yellow, Pigment Yellow 117, Pigment Yellow 128 and Pigment Yellow 138. Such pigments are commercially available in either powder or press cake form from a number of sources including, BASF Corporation, Engelhard Corporation and Sun Chemical Corporation. Examples of other suitable colored pigments are described in the Colour Index, 3rd edition (The Society of Dyers and Colourists, 1982). Representative examples of black pigments include various carbon blacks (Pigment Black 7) such as channel blacks, furnace blacks and lamp blacks, and include, for example, carbon blacks sold under the Regal(copyright), Black Pearls(copyright), Elftex(copyright), Monarch(copyright), Mogul(copyright), and Vulcan(copyright) trademarks available from Cabot Corporation (such as Black Pearls(copyright) 2000, Black Pearls(copyright) 1400, BlackPearls(copyright) 1300, Black Pearls(copyright) 1100, Black Pearls(copyright) 1000, Black Pearls(copyright) 900, Black Pearls(copyright) 880, Black Pearls(copyright) 800, Black Pearls(copyright) 700, Black Pearls(copyright) L, Elftex(copyright) 8, Monarch(copyright) 1400, Monarch(copyright) 1300, Monarch(copyright) 1100, Monarch(copyright) 1000, Monarch(copyright) 900, Monarch(copyright) 880, Monarch(copyright) 800, Monarch(copyright) 700, Mogul(copyright) L, Regal(copyright) 330, Regal(copyright) 400), Vulcan(copyright) P). Other suitable carbon blacks include, but are not limited to, Printex 40, Printex 80, Printex 300, Printex L, Printex U, Printex V, Special Black 4, Special Black 5, FW200, (the foregoing available from Degussa Corporation), Raven 780, Raven 890, Raven 1020, Raven 1040, Raven 1255, Raven 1500, Raven 5000, Raven 5250 (the foregoing available from Columbian Chemical Corporation) and MA100 and MA440 available from Mitsubishi Chemical Corporation. The colored pigment will typically have a wide range of BET surface areas, as measured by nitrogen adsorption. Preferably, the colored pigment has a surface area equal or greater than 85 m2/g, and more preferably equal or greater than and 100 m2/g, thereby corresponding to a smaller primary/aggregate particle size. Such surface areas have been found to provide for a more uniform distribution and efficient level of treating agent on the surface of the pigment and a higher percent yield of the surface-modified colored pigment after post processing techniques. If the preferred higher surface area of the colored pigment (thereby corresponding to a smaller particle size) is not readily available, it is well recognized by those skilled in the art that the colored pigment may be subject to conventional size comminution or reduction techniques, such as ball or jet milling, to reduce the pigment to the desired particle size.
Carbon product as used herein, is preferably capable of reacting with a diazonium salt to form the above-mentioned modified carbon product. The carbon may be of the crystalline or amorphous type. Examples include, but are not limited to, graphite, carbon black, vitreous carbon, carbon fibers, activated charcoal, and activated carbon. Finely divided forms of the above are preferred; also, it is possible to utilize mixtures of different carbons.
Also, any conventional amounts of the pigment used in the desired application can be present in compositions of the present invention. Preferably, with respect to an ink composition, for instance, the pigment can be present in an amount of from 1 wt % to about 25 wt % or higher, and more preferably from about 3 wt % to about 10 wt %, based on the weight of the ink composition.
For purposes of the present invention, one or more types of chemical groups can be attached to the same and/or different pigments.
The modified pigment products may be prepared by reacting the pigment as defined above with a diazonium salt in a liquid reaction medium to attach at least one group to the surface of the pigment. Preferred reaction media include water, any medium containing water, and any medium containing alcohol. Water is the most preferred medium.
To prepare the above modified pigment products, the diazonium salt need only be sufficiently stable to allow reaction with the pigment. Thus, that reaction can be carried out with some diazonium salts otherwise considered to be unstable and subject to decomposition. Some decomposition processes may compete with the reaction between the pigment and the diazonium salt and may reduce the total number of groups attached to the pigment. Further, the reaction may be carried out at elevated temperatures where many diazonium salts may be susceptible to decomposition. Elevated temperatures may also advantageously increase the solubility of the diazonium salt in the reaction medium and improve its handling during the process. The pigment can be reacted with a diazonium salt when present as a dilute, easily stirred, aqueous slurry, or as a more concentrated highly mixed slurry in water.
A preferred method of preparing the modified pigment products involves reducing the pigments to be modified to a size desirable for the particular end use application. If, of course, the pigment is already of an appropriate size, then no reduction in size is necessary. Generally, the size of the pigment can be the same size as the pigment sizes used conventionally for the particular end use applications. For instance, the average particle size of the pigment can be about 10 microns or less, and preferably about 5 microns or less. Preferably, for instance, in inkjet ink applications, the average pigment particle size is preferably less than about 1 micron and more preferably less than about 0.5 micron (e.g., a preferred range is about 0.01 micron to less than about 1 micron), and is preferably less than about 10 microns for coatings, toner, polymer, and rubber applications. If size reduction of the pigment to be modified is preferred, any method of reducing size can be used such as those described in T. C. Patton, xe2x80x9cPaint Flow and Pigment Dispersion,xe2x80x9d 2nd ed., Wiley, N.Y. (1979), incorporated herein by reference.
To attach a group having one or more of the formulas described above, a surfactant or polymer may be introduced to or contacted with the pigments. The surfactant or polymer comprises an organic group or polymeric group having at least one primary amine. A sufficient amount of time is provided to preferably adsorb the surfactant or polymer onto the pigment. Preferably, after adsorption occurs, a diazonium reaction can be conducted as described in U.S. Pat. Nos. 5,571,311 and 5,630,868, as well as 5,554,739 and PCT Publication WO-96/18688, all incorporated herein in their entirety by reference. In more detail, the preferred means of attaching the surfactant or polymer onto the pigments is by grinding, or reducing in size by other suitable mechanical or chemical means, the pigment in the presence of a solvent (e.g., aqueous or non-aqueous), preferably water. The surfactant or polymer can also be present during this size reduction step. Alternatively, the surfactant or polymer may be added after the size reduction step. An aqueous solution of a nitrite and an acid are then added separately or together to generate the diazonium reaction and form the diazonium salt which reacts with the pigment. This generation of the diazonium salt is preferably accomplished in situ with the pigment.
The surfactant or polymer is preferably any group capable of attaching onto a pigment through a diazonium reaction. In more detail, the surfactant or polymer will typically have a primary amine group attached to polymeric groups or organic groups, like aromatic or alkyl groups (e.g., the X substituent) set forth in the formulas above. In the diazonium reaction, the primary amine group will react to form nitrogen gas or other by-products which will then permit the group, for instance the aromatic group or alkyl group, to attach onto the pigment.
Typically known surfactants or polymers may be modified to comprise a primary amine using known techniques to those skilled in the art, such as esterification involving an aromatic or alkyl group and the surfactant or polymer and reduction of nitro groups on the aromatic or alkyl group to the corresponding primary amine groups. Nitration of the surfactant or polymer followed by reduction, or amination of the surfactant or polymer are some other techniques that may be used. Surfactants are commercially available under various well-known trademarks, such as the PLURONIC(copyright) series (BASF Corporation, Parsippany, N.J.), the TETRONIC(copyright) series (BASF Corporation, Parsippany, N.J.), the ARQUAD(copyright) series (Akzo Chemical Inc., Chicago, Ill.), the TRITON(copyright) series (Union Carbide Corp., Danbury, Conn.), the SURFONIC(copyright) series (Texaco Chemical Company, Houston, Tex.), the ETHOQUAD(copyright) series (Akzo Chemical Inc., Chicago, Ill.), the ARMEEN(copyright) series (Akzo Chemical Inc., Chicago, Ill.), the ICONOL(copyright) series (BASF Corporation, Parsippany, N.J.), the SURFYNOL(copyright) series (Air Products and Chemicals, Inc. Allentown, Pa.), and the ETHOMEEN(copyright) series (Akzo Chemical Inc., Chicago, Ill.), to name a few.
Other suitable surfactants for use in the present invention are disclosed in, for example, Kirk-Othmer, Encyclopedia of Chemical Technology, 3rd edition, Vol. 22 pages 332-386 and available manufacturing literature, including for example McCutcheon""s Emulsifiers and Detergents, NorthAmerican and International Edition (McCutcheon Division, The MC Publishing Co., 1991); Ash, The Condensed Encyclopedia of Surfactants (Chemical Publishing Co., Inc. 1989); and, Ash, What Every Chemical Technologist Wants to Know About . . . Emulsifiers and Wetting Agents, Volume I (Chemical Publishing Co., Inc. 1988), all of which are incorporated herein by reference.
For purposes of the invention, one or more surfactants, as described above, may be present. In addition, one or more surfactants can be combined with one or more polymeric groups as described above.
The level of treatment of the various groups attached on the pigment can be any amount and preferably is from about 0.10 to about 50 micromoles/m2, and more preferably is from about 0.30 to about 10 micromoles m2.
The modified pigment particles can then be subsequently subjected to cleaning procedures (e.g., washing or precipitation) which will remove substantially any excess reactants and unattached dispersants. The remaining slurry containing the modified pigment products can than be added to either aqueous or non-aqueous media and preferably with little or mild agitation to form stable (electrostatic, steric, and/or electrosteric) dispersions for a variety of end uses as described above.
The pigment products may be purified by washing, such as by filtration, centrifugation, or a combination of the two methods, to remove unreacted raw materials, byproduct salts and other reaction impurities. The products may also be isolated, for example, by evaporation or it may be recovered by filtration and drying using known techniques to those skilled in the art. Dispersions of the pigments of the present invention may be further purified or classified to remove impurities and other undesirable free species which can co-exist in the dispersion as a result of the manufacturing process. In a preferred embodiment, the cationic pigment dispersions are subject to a classification step, such as centrifugation, to substantially remove particles having a size above about 1.0 micron, preferably above about 0.5 micron. In addition, the dispersion is preferably purified to remove any undesired free species, such as unreacted treating agent. Known techniques of ultrafiltration/diafiltration using a membrane or ion exchange may be used to purify the dispersion and remove a substantial amount of free ionic and unwanted species. Also preferred is an optional exchange of counterions whereby the counterions that form a part of the surface-modified pigment are exchanged or substituted with alternative counterions utilizing known ion exchange techniques such as ultrafiltration, reverse osmosis, ion exchange columns and the like. Particular examples of counterions that can be exchanged include, but are not limited to, Na+, K+, Li+, NH4+, Ca2+, Mg2+, Clxe2x88x92, NO3xe2x88x92, NO2xe2x88x92, acetate, carboxylate, and Brxe2x88x92. Such additional classification and purification methods are more fully described in U.S. patent application No. 09/240,291, filed Jan. 29, 1999, the disclosure of which is fully incorporated herein by reference.
Uses of the Modified Pigment Products
The modified pigment products of this invention may be used in the same applications as conventional pigments, like carbon blacks. The groups attached to the pigment, however, can be used to modify and improve the properties of a given pigment for a particular use.
Modified pigment products according to the invention can be used in a number of end use applications. These uses include, for example, plastic compositions, aqueous and non-aqueous inks, aqueous and non-aqueous coatings, rubber compositions, toner compositions, paper products, and textile and fiber compositions. The following paragraphs describe these uses generally and examples of each are shown below.
The modified pigment products of this invention can be used as colorants in a plastic material. The modified pigment products of the invention can also be used to impart conductivity to a plastic material. The modified pigment products of the invention may give an increased rate of dispersion or improved quality of dispersion over the corresponding untreated pigment. These improvements offer an economic advantage in plastic manufacture and in value of the finished product, respectively. Using the modified pigment products of the invention may improve impact strength of the plastic. Thus, the invention relates to an improved plastic composition comprising a plastic and the modified pigment product.
As with conventional pigments, the modified pigment products can be used with a variety of plastics, including but not limited to plastics made from thermoplastic resins, thermosetting resins, or engineered materials, for example, composites. Typical kinds of thermoplastic resins include: (1) acrylonitrile-butadiene-styrene (ABS) resins; (2) acetals; (3) acrylics; (4) cellulosics; (5) chlorinated polyethers; (6) fluorocarbons, such as polytetrafluoroethylene (TFE), polychlorotrifluoroethylene (CTFE), and fluorinated ethylene propylene (FEP); (7) nylons (polyamides); (8) polycarbonates; (9) polyethylenes (including copolymers); (10) polypropylenes (including copolymers); (11) polystyrenes; (12) vinyls (polyvinyl chloride); (13) thermoplastic polyesters, such as polyethylene terephthalate or polybutylene terephthalate; (14) polyphenylene ether alloys; and blends and alloys of the above with rubber modifiers. Typical thermosetting resins include: (1) alkyd,; (2) allylics; (3) the aminos (melamine and urea); (4) epoxies; (5) phenolics; (6) polyesters; (7) silicones; and (8) urethanes.
Generally, the modified pigment product is added like any other pigment to the plastic used to form a plastic premix. This can be done, for example, in a dry mix or a melt stage. The modified pigment product may also be incorporated on or in a plastic by adding it to a solvent, where the plastic is soluble or partially-soluble, followed by removal of the solvent (e.g., by evaporation). The modified pigment products of the invention may be used in combination with other conventional additives in plastic compositions. According to the invention, the term plastic composition includes, but is not limited to, any plastic material, article, goods, surface, fabric, sheet, film, and the like. For example, plastic materials include automotive parts, siding for homes, liners for swimming pools, roofing materials, packaging materials, synthetic fibers, food, and storage containers, light absorbing applications (e.g., bar codes), and any variety of other household or industrial items.
The modified pigment products of this invention are also useful in aqueous and non-aqueous ink formulations. Thus, the invention provides an ink composition comprising an ink vehicle and a modified pigment product. Other known ink additives may be incorporated into the ink formulation. Typical inks include, but are not limited to: lithographic, letterpress, flexographic, gravure, screening, phase change ink jet inks, and ink jet applications.
In general, an ink consists of four basic components: (1) a colorant, (2) a vehicle or varnish which functions as a carrier during printing, (3) additives to improve printability, drying, and the like, and (4) solvents to adjust viscosity, drying and the compatibility of the other ink components. For a general discussion of the properties, preparation and uses of inks, see The Printing Manual, 5th Ed., Leach et al, Eds. (Chapman and Hall, 1993) incorporated herein by reference. Various ink compositions are also disclosed, for example, in U.S. Pat. Nos. 2,833,736; 3,607,813; 4,104,833; 4,770,706; and 5,026,755, incorporated in their entirety herein by reference.
The modified pigment products of the invention, either as predispersion or as a solid, can be incorporated into an ink formulation using standard techniques. Use of a water dispersible or solvent-dispersible modified pigment product of the invention can provide a significant advantage and cost savings by reducing or eliminating the milling steps generally used with other conventional pigments.
Flexographic inks represent a group of ink compositions. Flexographic inks generally include a colorant, a binder, and a solvent. The modified pigment products of the invention are useful as flexographic ink colorants.
The modified pigment products of the invention can be used in news inks. For example, a news ink composition may comprise an ink vehicle (e.g., water), the modified pigment products of the invention, a resin, and optional conventional additives such as antifoam additives or a surfactant.
The modified pigment products of the invention may also be used in phase change (hot melt) inks. Phase change inks generally include at least one colorant and at least one phase change or wax carrier (e.g., a fatty amide-containing material like a mixture of a tetra amide compound and a mono-amide compound, or an alkanolamides and polyethylene glycol mixture). The phase change ink is in a solid phase at ambient temperature and in a liquid phase at an elevated operating temperature of the printer. When the ink is heated it melts to form a low viscosity fluid that can be ejected as droplets. Upon jetting, heated droplets impact on a substrate, and cool to ambient temperature forming films of uniform thickness. Subsequent impaction of the droplets on the substrate may also occur, depending upon the type of printer used. Use of a modified pigment product can provide a significant advantage in dispersion stability and carrier compatibility over conventional pigments and in light-fastness over dyes.
The modified pigments of the present invention can also be used in lithographic or flexographic printing. For example, the ink or fountain solution used in the printing process can contain the modified pigments of the present invention.
The modified pigments of the present invention can also be used in the manufacture of lithographic printing plates, such as infrared or near-infrared laser-imageable printing plates. Typically, imaging occurs when the plate is exposed to radiation having wavelengths of between 800 and 1100 nm. Generally, an infrared or near-infrared laser-imageable lithographic printing plate includes at least the following layers: a grained-metal or polyester plate or sheet-like substrate and a radiation-absorptive layer coated thereon. Protective layers for the substrate or the surface of the coated plate may also be used in the present invention. When coated onto the substrate, the protective layer can also serve as an adhesion-promoting primer. Other layers may be used, for example, to improve adhesion between layers and durability of the printing plate. The radiation-absorptive layer contains the modified pigment of the present invention along with other conventional ingredients, such as resins and binders. In the imaging process, a lithographic printing plate is selectively exposed to a laser output or other source capable of removing or chemically modifying the radiation-absorbent layer or layers adjacent thereto. The laser output will define a pattern on the printing plate and remove or modify only those portions of the radiation-absorptive layer which define the pattern. Afterwards, the printing plate can be further developed by subjecting it to a solvent capable of removing the imaged layer(s), if any remains, which defines the same pattern. The details of the various conventional components and techniques for such printing plates are described in U.S. Pat. No. 5,493,971; EP 0 803 771 A1; EP 0 770 494 A2; EP 0 770495 A1; as well as PCT Publication WO-98/31550 and the patents and publications referenced therein, all of which are incorporated in their entirety by reference herein.
The modified pigment products of the invention may also be used in coating compositions such as paints or finishes, or the like. Thus, an embodiment of the invention is a coating composition comprising an aqueous or non-aqueous vehicle, resin or binder, and a modified pigment product. Other known coating additives may be incorporated in the coating compositions. See for examples, McGraw-Hill Encyclopedia of Science and Technology, 5th Ed. (McGraw-Hill, 1982) incorporated herein by reference. See also U.S. Pat. Nos.5,051,464; 5,319,044; 5,204,404; 5,051,464; 4,692,481; 5,356,973; 5,314,945; 5,266,406; and 5,266,361, incorporated in their entirety by reference herein.
The modified pigment products of the invention, either as a predispersion or as a solid, can be incorporated into a coating composition using standard techniques. Use of a water or solvent dispersible modified pigment product provides a significant advantage and cost savings by reducing or eliminating the milling steps generally used with other conventional pigments.
The modified pigment products of the invention may also be used in paper (compositions. Accordingly, the invention relates to a paper product comprising paper pulp and at least one modified pigment product.
The modified pigment products of the invention, either as a solid or a predispersion, can be incorporated into paper pulp using standard papermaking techniques as with conventional pigments. Use of a water or solvent dispersible modified pigment product discussed above may provide a significant advantage and cost savings by reducing or eliminating the steps generally used to disperse other conventional pigments.
The paper products of the invention may incorporate other known paper additives such as sizing agents, retention aids, fixatives, fillers, defoamers, deflocculating agents, and the like. Advantageously, the water or solvent dispersible modified pigment products discussed above are retained more efficiently at low loading levels when compared to the untreated pigments when retention aids and acidic or alkaline sizing agents are used.
The modified pigment products of the invention may also be used, as with conventional pigments, as pigments, fillers, and reinforcing agents in the compounding and preparation of rubber compositions. Accordingly, the invention relates to a rubber or elastomeric composition containing at least one rubber or elastomer and at least one modified pigment.
Carbon blacks, for example, are useful in the preparation of rubber vulcanizates such as those in tires. It is generally desirable in the production of tires to utilize carbon blacks which produce tires with satisfactory abrasion resistance and hysteresis performance. The treadwear properties of a tire are related to abrasion resistance. The greater the abrasion resistance, the greater the number of miles the tire will last without wearing out. The hysteresis of a rubber compound means the difference between the energy applied to deform a rubber compound, and the energy released as the rubber compound recovers to its initial undeformed states. Tires with lower hysteresis values reduce rolling resistance and therefore are able to reduce the fuel consumption of the vehicle utilizing the tire. Thus, it is particularly desirable to have carbon black products capable of imparting greater abrasion resistance and lower hysteresis in tires.
The modified pigment products, and preferably the modified carbon black products of this invention are useful in both natural and synthetic rubber compositions or mixtures of natural and synthetic rubbers. Carbon black products comprising an aromatic sulfides group are preferred for this use. The carbon black products of the invention can be used in rubber compositions which are sulfur-cured or peroxide-cured.
The modified pigment products may be mixed with natural or synthetic rubbers by normal means, for examples by milling. Generally, amounts of the modified pigment produced ranging from about 10 to about 250 parts by weight can be used for each 100 parts by weight of rubber in order to impart a significant degree of reinforcement. It is, however, preferred to use amounts varying from about 20 to about 100 parts by weight of carbon black per 100 parts by weight of rubber and especially preferred is the utilization of from about 40 to about 80 parts of carbon black; per 100 parts of rubber.
Rubbers suitable for use with the present invention are natural rubber and its derivatives such as chlorinated rubber. The modified pigment products of the invention may also be used with synthetic rubbers such as: copolymers of from about 10 to about 70 percent by weight of styrene and from about 90 to about 30 percent by weight of butadiene such as copolymer of 19 parts styrene and 81 parts butadiene, a copolymer of 30 parts styrene and 70 parts butadiene, a copolymer of 43 parts styrene and 57 parts butadiene and a copolymer of 50 parts styrene and 50 parts butadiene; polymers and copolymers of conjugated dienes such as polybutadiene, polyisoprene, polychloroprene, and the like, and copolymers of such conjugated dienes with an ethylenic group-containing monomer copolymerizable therewith such as styrene, methyl styrene, chlorostyrene, acrylonitrile, 2-vinyl-pyridine, 5-methyl 2-vinylpyridine, 5-ethyl-2-vinylpyridine, 2-methyl-5-vinylpyridine, alkyl-substituted acrylates, vinyl ketone, methyl isopropenyl ketone, methyl vinyl either, alphamethylene carboxylic acids and the esters and amides thereof such as acrylic acid and dialkylacrylic acid amide; also suitable for use herein are copolymers of ethylene and other high alpha olefins such as propylene, butene-1 and pentene-1.
The rubber composition of the present invention can therefore contain at least one elastomer, curing agents, reinforcing filler, a coupling agent, and, optionally, various processing aids, oil extenders, and antidegradents. In addition to the examples mentioned above, the elastomer can be, but is not limited to, polymers (e.g., homopolymers, copolymers, and terpolymers) manufactured from 1,3 butadiene, styrene, isoprene, isobutylene, 2,3-dimethyl- 1,3 butadiene, acrylonitrile, ethylene, propylene, and the like. It is preferred that these elastomers have a glass transition point (Tg), as measured by DSC, between xe2x88x92120xc2x0 C. and 0xc2x0 C. Examples of such elastomers include poly(butadiene), poly(styrene-co-butadiene), and poly(isoprene).
Advantageously, the modified pigment products, and especially the modified carbon black products of the present invention can impart improved abrasion resistance and/or reduced hysteresis to rubber or elastomeric compositions containing them.
The modified pigment products of this invention may also be used to color fibers or textiles. Preferred modified pigment products for this use are the dispersible modified pigment products. Accordingly, the invention relates to fiber and textile compositions comprising a fiber or textile and a modified pigment product. Fibers suitable for use comprise natural and synthetic fibers such as cotton, wool, silk, linen, polyester and nylon. Textiles suitable for use comprise natural and synthetic fibers such as cotton, wool, silk, linen, polyester and nylon. Preferably natural fibers and textiles comprising cotton, wool, silk, and linen are used.
The modified pigment products of the present invention may be colored by means known in the art to color fibers and textiles with, for example, direct and acid dyes. Also, the modified pigments can be incorporated into fibers by spinning techniques, such as wet spinning, dry spinning, and melt spun techniques. For a general discussion of coloring with dyes, see Kirk-Othmer Encyclopedia of Chemical Technology, Vol 8pp 280-350 xe2x80x9cDyes, Application and Evaluationxe2x80x9d (John Wiles and Sons, 1979), incorporated herein by reference. Use of a water or solvent dispersible modified pigment product discussed above provides a method for coloring these materials with a lightfast colorant.
The present invention also relates to toner compositions comprising toner resin particles and the modified pigment particles of the present invention. Conventional additives as described in U.S. Pat. Nos. 5,278,018; 5,510,221; 5,275,900; 5,571,654; and 5,484,575; and EP 0 270-066A1 can be used and these patents are incorporated herein by reference.
The present invention also relates to an inkjet ink composition comprising an aqueous or non-aqueous vehicle and a modified pigment product. In contrast to conventional pigment,, the modified pigment products for use in the inkjet ink of the present invention are not difficult to disperse in an aqueous or non-aqueous vehicle. The modified pigment products do not necessarily require a conventional milling process, nor are additional dispersants necessarily needed to attain a usable ink. Preferably, the modified pigment products only require low shear stirring or mixing to readily disperse the pigment in water or other solvent.
Formation of an inkjet ink containing a vehicle and stably dispersed modified pigment product as pigment can be performed with a minimum of components and processing steps when the above modified pigment products are utilized. Such an ink may be used in any inkjet printer known in the art. Preferably, in inkjet inks of the present invention, the modified pigment products are present in an amount of less than or equal to 20% -25% by weight of the inkjet ink. It is also within the bounds of the present invention to use an inkjet ink formulation containing a mixture of unmodified pigment with the modified pigment products of the present invention. Common additives such as those discussed below may be added to the dispersion to further improve the properties of the inkjet ink.
In particular, a humectant may be added to reduce the rate of evaporation of water in the ink to minimize clogging. If the ink begins to dry out, the humectant concentration increases and evaporation decreases further. Humectants may also affect other properties of the ink and prints made therefrom, such as viscosity, pH, surface tension, optical density, and print quality. Preferred humectants include ethylene glycol, propylene glycol, diethylene glycols, glycerine, dipropylene glycols, polyethylene glycols, polypropylene glycols, amides, ethers, carboxylic acids, esters, alcohols, organosulfides, organosulfoxides, sulfones, alcohol derivatives, carbitol, butyl carbitol, cellosolve, ether derivatives, amino alcohols, and ketones.
Biocides such as benzoate or sorbate salts are important in preventing bacterial growth. Bacteria are often larger than ink nozzles and can cause clogging and other problems. Binders attach to the substrate to hold the colorant on the paper. Examples include polyester, polyester-melanine, styrene-acrylic acid copolymers, styrene-acrylic acid-alkyl acrylate copolymers, styrene-maleic acid copolymers, styrene-maleic acid-alkyl acrylate copolymers, styrene-methacrylic acid copolymers, styrene-methacrylic acid-alkyl acrylate copolymers, styrene-maleic half ester copolymers, vinyl naphthalene-acrylic acid copolymers, vinyl naphthalene-maleic acid copolymers, and salts thereof. Drying accelerating agents promote evaporation of the ink once the ink is placed in the paper. These include sodium lauryl sulfate, N,N-diethyl-m-toluamide, cyclohexylpyrrolidinone, and butyl carbitol. Penetrants such as alcohols, sodium lauryl sulfate, esters, and ketones allow the ink to penetrate the surface of the paper. Alcohols may also be used to increase the rate of drying of the liquid ink, and surfactants like detergents and soap reduce the surface tension to allow the ink to spread on the substrate.
Additionally, the modified pigment products-based inkjet inks may incorporate some dye to modify color balance and adjust optical density. Such dyes include food dyes, FD and C dyes, derivatives of phathalocyanine tetrasulfonic acids, including copper phthalocyanine derivates, tetra sodium salts, tetra ammonium salts, tetra potassium salts, tetra lithium salts, and the like.
Polymers or oligomers maybe added to inkjet inks based on the modified pigment products. The images created from such an ink may be water-insoluble upon polymerization or cross-linking of the added polymers or oligomers.
Additionally, in preparing inkjet inks utilizing the modified pigment products of the present invention, sequential filtration of the inks through filters of descending size or centrifugation or both may be used to obtain a more desirable final product. For instance, filtering first with, a 3.0 micron filter and then filtering with a 1.0 micron filter, and so on, as desired. In addition, the size of the modified pigment products in the inkjet inks is preferably no larger than about 2 microns. More preferably, the size of the modified pigment product is one micron or less.
Advantageously, the inkjet inks of the invention have excellent stability over tine and a wide range of temperatures, have desirable viscosities and surface tensions, and when printer, have good optical density, print clarity, rub resistance, and waterfastness can be obtained when the inkjet ink contains certain stryenated acrylics that impart this property. For instance, one such stryenated acrylic has a molecular weight of about 4200, a polydispersibility of about 2, and acid number of about 215, a softening point of about 128xc2x0 C., and a Tg of about 67xc2x0 C. A commercially available example is JONCRYL 58 acrylic (JONCRYL is a registered trademark of Johnson Polymer, Racine Wis.), which is a solution of Joncryl 680.
The present invention will be further clarified by the following examples, which are intended to be purely exemplary of the present invention.